Implementation of MySQL executing multiple statements at a time and common problems

MySQL supports multiple statement execution in a single query string by specifying parameters to the link:

 
// Link time setting  
mysql_real_connect( ..., CLIENT_MULTI_STATEMENTS ); 
// or  
// Halfway to specify  
mysql_set_server_option( mysql, MYSQL_OPTION_MULTI_STATEMENTS_ON ); //mysql Is the name of the connection  

When using the multi-statement function, 1 must read the entire resault set, otherwise an error will occur: Commands out of sync; you can't run this command now
The official recommended execution statement is this:

 
do 
{ 
    /* Process all results */ 
    ... 
    printf( "total affected rows: %lld", mysql_affected_rows( mysql ) ); 
    ... 
    if( !( result mysql_store_result( mysql ) ) ) 
    { 
        printf( stderr, "Got fatal error processing query\n" ); 
        exit(1); 
    } 
    process_result_set(result);    /* client function */ 
    mysql_free_result(result); 
}while( !mysql_next_result( mysql ) ); 

If you're just inserting SQL statements that don't need to return a value, you'll have to read the entire resault set and release it.

 
do 
{ 
    result = mysql_store_result( mysql ); 
    mysql_free_result(result); 
}while( !mysql_next_result( mysql ) );